1. Field of the Invention
The present invention relates to a tube-side sequentially pulsable-flow, shell-and-tube heat exchanger apparatus and a chemical processing system comprising and methods of heat exchange employing the same.
2. Description of the Related Art
U.S. Pat. No. 3,681,200 mentions a vertically oriented, impeller containing “shell-and-tube fermentor.” U.S. Pat. No. 6,084,125 mentions a vertically oriented, impeller containing “shell-and-tube reactor.” U.S. Pat. Nos. 3,759,318 and 3,965,975 each mention a type of horizontally oriented, impeller containing “mixing device” comprising a plurality of tubes. U.S. Pat. No. 4,823,866 mentions an impeller-containing “stirred vessel” that also contains a heat exchanger apparatus comprising a plurality of tubes. U.S. Pat. No. 5,379,832 mentions a “shell and coil heat exchanger.” All of the aforementioned shell-and-tube fermentor, shell-and-tube reactor, mixing devices, stirred vessel, and shell and coil heat exchanger lack pulsed flow capability. Chen, Y. and Zhao, J. mention Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchanger, HVAC Technologies for Energy Efficiency, Vol. IV 6-3, ICEBO2006, Shenzhen, China. A pulsed solenoid valve device for modulating refrigerant flow in a water chiller or water chiller evaporator is mentioned in Masterclass: Shell & Tube Evaporators-Part 16, ACR-news.com, Apr. 1, 2007, Faversham House Group Ltd., South Croydon, United Kingdom. A drawback of the pulsed solenoid valve device is that it works by stopping and restarting the entire refrigerant flow in an all or nothing paradigm. Detrimental effects of such stopping and restarting include a lower overall refrigerant flow rate than would be achievable under same conditions but lacking the stopping feature and an increased likelihood that heterogeneous material (e.g., contaminants) in the refrigerant will settle into a hold-up void when flow is stopped, and thereby foul the water chiller.
U.S. Pat. No. 6,955,461 B2 mentions a tickler impeller and agitation system for use in slurry reactors and storage tanks.
Fouling of tubes and concomitant reduction of heat exchange efficiency in conventional shell-and-tube heat exchangers still plagues industries that employ such heat exchangers. Such an improved heat exchanger would be especially useful for fouling-prone process fluids such as, for example, heterogeneous process fluids comprising a liquid component and a fouling component (e.g., a contaminant or process component) that is a particulate solid, an insoluble second liquid, or both; or a liquid reactant (e.g., monomer) prone to create a solid (e.g., by precipitation of a component dissolved therein or by reaction (e.g., polymerization) to produce an insoluble product), and thereby foul the tubes. The chemical industry, in particular, desires a shell-and-tube heat exchanger with improved operating performance such as, for example, an enhanced heat transfer rate, decreased tube fouling rate, or both. Ideally, the improved shell-and-tube heat exchanger would operate by maintaining an average (overall) flow rate of process fluid and only locally vary tube-specific flow rates of a fouling-prone process fluid moving through the tubes. Further, it would be desirable if the improved shell-and-tube heat exchanger inhibits agglomeration of solids in a slurry or dispersion process fluid, especially agglomeration in an inlet plenum, tubes, outlet plenum, or a combination thereof of the improved shell-and-tube heat exchanger.